Deck 4: Archaeal Cell Structure

Question 1

Some archaeons are symbionts in animal digestive tracts.

Answer 1

True

Question 2

Bacterial and archaeal ribosomes are known as _____ ribosomes,based on their sedimentation coefficient.

A)50S
B)30S
C)80S
D)70S

Answer 2

D

Question 3

_______ are the site of protein synthesis in the cell.

Answer 3

Ribosomes

Question 4

Methanogens may contribute to the greenhouse effect and global warming due to methane production.

Question 5

The DNA of some archaeons is stabilized by association with archaeal histone proteins forming particles resembling eukaryotic nucleosomes.

Question 6

The hydrocarbons found in the membranes of archaea are identical to those found in bacteria.

Question 7

Which statement correctly describes archaeal cell walls?

A)Some have an outer layer of complex polysaccharide.
B)Some have an outer layer of protein.
C)Many have peptidoglycan.
D)Some have an outer layer of complex polysaccharide and some have an outer layer of protein.

Question 8

Some archaeal cells lack a cell wall.

Question 9

External structures that are found in Archaea but not Bacteria are _________.

A)pili
B)flagella
C)hami
D)peptidoglycan

Question 10

Which of the following is not true about archaeal ribosomes?

A)They are 70S like bacterial ribosomes.
B)They may possess ribosome binding sites homologous to bacterial Shine-Dalgarno sequences.
C)They have similar antibiotic sensitivities to those of bacteria.
D)All of these are true about archaeal ribosomes.

Question 11

Archaeal flagella are superficially similar to bacterial flagella,although archaeal flagella are much thicker than bacterial flagella.

Question 12

The primary lipid components of the membranes of extreme thermophiles are

A)sulfolipids.
B)cholesterol.
C)40 carbon diglycerol tetraethers.
D)20 carbon diglycerol diethers.

Question 13

A feature unique to some archaeal plasma membranes is that they may

A)consist of a lipid bilayer that lacks integral membrane proteins.
B)consist of a lipid bilayer with embedded proteins.
C)contain sterols such as cholesterol.
D)consist of a lipid monolayer.

Question 14

A(n)__________ layer is a layer of protein or glycoprotein that exhibits a pattern resembling floor tiles.

Question 15

Cell walls of most Archaea and bacteria contain peptidoglycan.

Question 16

_______ is a peptidoglycan-like molecule found in the cell walls of some archaea.

Question 17

Molecules or regions of molecules that readily interact with water are said to be __________,whereas molecules or regions of molecules that are insoluble in water or do not readily interact with water are said to be hydrophobic.

Question 18

Many archaeal genomes include chromosomes and plasmids.

Question 19

Unlike members of the Bacteria,most archaeans have linear chromosomes.

Question 20

A peptidoglycan-like polymer found in the cell walls of some Archaea is called __________.

Question 21

Which of the following is the most unique aspect of archaeon cell envelopes?

A)The plasma membrane is composed of phospholipids
B)The cell walls contain a modified type of peptidoglycan
C)Archaeon capsules can be composed of protein or polysaccharide.
D)Some archaeons have lipid monolayers in their plasma membrane.

Question 22

Select the correct statement about archaeal ribosomes.

A)Archaeal ribosomal proteins are more similar to bacterial ribosomal proteins than to eukaryotic ribosomal proteins.
B)Archaeal ribosomes are susceptible to antibiotics,similar to bacterial ribosomes.
C)Archaeal ribosomes have subunits that are identical in shape and chemical components to those of bacteria.
D)The chemical components of archaean ribosomes are more similar to those of eukaryotic ribosomes than to those of bacterial ribosomes.

Question 23

Some researchers have suggested that archaeal flagella be renamed as archaella because

A)they are more slender than bacterial flagella.
B)some archaeon flagella don't have hooks.
C)All of the choices are correct.
D)archaean flagella are composed of more than one type of flagellin subunit.
E)archaean flagella are solid and not hollow.

Question 24

Which cellular shape is seen among members of domain Bacteria that is not found among the domain Archaea?

A)Cocci
B)Bacilli
C)Comma shaped
D)Spiral or corkscrew shapes

Question 25

You are studying a newly discovered prokaryotic microorganism and are attempting to determine whether it will be classified in the domain Bacteria or in the domain Archaea.All of the following would be helpful in making that distinction except

A)Sequence of small subunit ribosomal RNA
B)Type of membrane lipids
C)Presence or absence of peptidoglycan in cell walls
D)Presence or absence of double-stranded circular DNA genome

Question 26

In terms of membrane lipids,the plasma membranes of archaeons are more similar to those of the eukaryotes than to membranes of bacteria.

Question 27

Archaeal cell walls

A)are disrupted by treatment with lysozyme or penicillin.
B)are similar to those of gram-negative bacteria.
C)lack murein and D-amino acids.
D)include orthomureine.

Question 28

Which of the following contribute(s)to the differences between the members of the Domain Archaea and the Domain Bacteria?

A)Archaea lack muramic acid.
B)Archaea have isopranyl glycerol ethers rather than fatty acid esters in their membrane lipids.
C)Archaea differ from bacteria in their tRNA composition,ribosome structure,and antibiotic sensitivity.
D)All of the choices are correct.

Question 29

Which type of membrane transport is most important for nutrient acquisition in nutrient poor environments?

A)Simple diffusion
B)Facilitated diffusion through channel proteins
C)Facilitated diffusion through membrane carrier proteins
D)Active transport

Question 30

Archaeal and Bacterial pili are identical in structure and function.

Question 31

Which statement correctly explains the Gram stain reaction of archaeal cells?

A)They are Gram-positive due to the pseudomurein layer in their cell walls.
B)They are Gram-negative due to the lack of peptdoglycan in their cell walls.
C)They don't stain - basic dyes used in the Gram stain don't adhere to archaeal cells.
D)Some are Gram-positive and some are Gram-negative due to the diverse chemical structure.

Question 32

The Archaea generally lack which of the following that are normally found in gram-negative bacteria?

A)Outer membrane
B)A complex peptidoglycan network
C)Lipopolysaccharide
D)All of the choices are correct.

Question 33

__________________ are hollow tube-like structures that hold some archaeal daughter cells together after cell division while____________ are grappling hook-like structures that appear to attach archaeal cells to surfaces.

A)Pili; hami
B)Cannulae;hami
C)Hami; fimbriae
D)Cannulae; pili

Question 34

Which of the following structures are external to both Bacterial and Archaeal cells?

A)Ribosomes
B)Hami
C)Pili
D)Peptidoglycan

Question 35

Penicillin inhibits bacterial growth by preventing the cross-linking during peptidoglycan synthesis.Why does penicillin not inhibit growth of archaeal cells?

A)Archaeal cells do not have a cell wall.
B)Most archaeal cells have a cell wall,but it is not composed of peptidoglycan.
C)Penicillin is unable to penetrate the lipid outer membrane that blocks access of penicillin to the peptidogycan crosslinking enzymes.
D)Pencillin is unable to penetrate the S layer to reach the peptidoglycan layer underneath.

Question 36

The cell membranes of wall-less archaeons are strengthened by

A)diglycerol ethers.
B)glycoprotein or protein layers.
C)pseudomurein.
D)diglycerol tetraethers.

Question 37

Archaeal membranes contain which of the following lipids?

A)Phospholipids
B)Sulfolipids
C)Glycolipids
D)All of the choices are correct.

Question 38

Archaeons power their flagella by proton motive force (PMF),whereas bacteria empower their flagella by ATP hydrolysis.

Question 39

One type of archaeon,Haloquadratum walsbyi,is shaped like a postage stamp with dimensions of 2 µm x 3 µm x 0.25 µm.What advantage would this shape provide?

A)This shape enables this bacteria to float on surfaces and obtain better light exposure.
B)This shape increases the surface to volume ratio enabling more efficient nutrient uptake.
C)This shape is difficult for phagocytic cells to attach to and engulf.
D)This shape is more conducive to the formation of biofilm communities.

Question 40

Diglycerol tetraether lipids

A)are a characteristic feature of thermophilic Archaea.
B)tend to make the membrane less rigid.
C)are found in some bacteria and some Archaea.
D)form typical bilayer membranes in thermophilic Archaea of the genus Thermoplasma.

Question 41

You are working with a newly described microorganism that has flagella that are solid,10 nm in diameter,and composed of more than one type of flagellin subunit.Based on the type of flagella,which type of organism is this?

A)Archaea
B)Bacteria
C)Protozoa
D)Algae